(Android™) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

Chilkat Android™ Downloads Android™ Java Libraries Android C/C++ Libraries

// Important: Don't forget to include the call to System.loadLibrary
// as shown at the bottom of this code sample.
package com.test;

import android.app.Activity;
import com.chilkatsoft.*;

import android.widget.TextView;
import android.os.Bundle;

public class SimpleActivity extends Activity {

  private static final String TAG = "Chilkat";

  // Called when the activity is first created.
  @Override
  public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    // This example assumes the Chilkat API to have been previously unlocked.
    // See Global Unlock Sample for sample code.

    // Load an EC key from some format..
    CkPrivateKey privKey = new CkPrivateKey();

    // This loads an ECDSA key from an unencrypted PEM file (no password required).
    boolean success = privKey.LoadAnyFormatFile("qa_data/ecc/openssl_ecc_privKey.pem","");
    if (success == false) {
        Log.i(TAG, privKey.lastErrorText());
        return;
        }

    // The key type should be "ecc" to indicate an EC key.
    Log.i(TAG, "key type = " + privKey.keyType());

    // What is the size of the private key in bits?
    Log.i(TAG, "size in bits = " + String.valueOf(privKey.get_BitLength()));

    // Get the private and public EC key parts in raw hex format:
    CkStringBuilder sbPubKeyHex = new CkStringBuilder();
    String privKeyHex = privKey.getRawHex(sbPubKeyHex);

    // If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).
    Log.i(TAG, "private key = " + privKeyHex);

    // The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)
    Log.i(TAG, "public key = " + sbPubKeyHex.getAsString());

    // Sample output:
    // key type = ecc
    // size in bits = 256
    // private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
    // public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a

  }

  static {
      System.loadLibrary("chilkat");

      // Note: If the incorrect library name is passed to System.loadLibrary,
      // then you will see the following error message at application startup:
      //"The application <your-application-name> has stopped unexpectedly. Please try again."
  }
}